The present invention relates to a switch coupling assembly for coupling switch handles, and more particularly, pertains to a switch coupling assembly which couples a plurality of electric switch handles and a spacer in an aligned orientation with a threaded rod, wherein the spacer and/or the switch handles are also threaded to prevent inadvertent movement of the rod.
In many electrical installations, it may be desirable to provide simultaneous switching of electric switch handles, e.g., circuit breaker handles, of separate electrical units. This may occur, for example, when circuits are protected by separate single-pole circuit breakers but it is necessary for the circuits to remain in the same conducting state, or for circuits protected by two-pole circuit breakers that require both legs of the circuit breaker to simultaneously disconnect. Thus, it becomes necessary to connect two or more switches or circuit breaker handles together so that they may operate simultaneously and actuate or disconnect at the same time.
Specifically, in power distribution applications this requirement may be found in multiwire branch circuits which consist of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system. Multiwire branch circuits can be extremely dangerous if the ungrounded circuit conductors are not all deenergized when equipment supplied from a multiwire circuit is being serviced. For this reason, all ungrounded conductors of a multiwire branch circuit must be simultaneously disconnected to reduce the risk of electric shock to users working on equipment.
For example, in 240 volt alternating current (VAC) circuits, connecting two switches is commonly required because one switch or circuit breaker controls one 120 VAC leg of the circuit while the second switch or circuit breaker controls the other “out of phase” 120 VAC leg. In a 120/240 VAC system, the center winding of the transformer is tied to ground so a 240 VAC circuit is achieved, but very dangerous amounts of voltage are also produced. Unless both legs are broken during service and maintenance activities, a functional power circuit exists between the unbroken leg and any grounded metal part. Thus, it is a necessity to assure that when the circuit is deenergized, both legs are also deenergized. This can be done by a mechanical device which physically connects the operating handles of the two switches or circuit breakers together so that the legs are always in the same conducting state.
Existing methods for switch ties generally involve brackets, clips or bars that must be attached, either by fasteners or protrusions, to the switches or brackets of interest. Often, they are clumsy additions to the pre-existing design of the switch or breaker. Therefore, an improved simple and unobtrusive switch tie device is desired. It is an additional object of the present invention to prevent axial motion of a coupling rod without the use of a retainer or washer.